The aim of the study is to explore short and longer-term effects of the Endobarrier™ implantation on insulin resistance and beta-cell function assessed by repeated Botnia clamps. In addition changes in gut peptides and gut permeability after implantation of a removable duodeno-jejunal bypass device to induce diabetes remission in obese subjects with sub-optimally controlled type 2 diabetes mellitus will be determined. Further changes in body weight and body composition, the change in global cardiovascular risk from baseline to 12 months, estimated using the UKPDS risk engine will be recorded.